Ditopic Ambiphilicity of an Anionic Dimetalloborylene Complex

In early reports, the boron atom of the anionic borido complexes [{(η5-C5H4R)­(OC)2Mn}2B]− (R = H, Me) showed nucleophilic behavior in the presence of electrophiles such as methyl iodide and group 11 metal chlorides, akin to the ground-breaking boryl lithium of Yamashita and Nozaki. Later, a reaction with the well-known transition metal Lewis base [Pt­(PCy3)2] suggested the possibility of boron-centered electrophilicity. In this paper we elucidate a third reactivity profile of the anion, nucleophilic substitution on heavier halides of group 14 metals by a manganese center. Meanwhile, other group 11 halides were found to interact with the boron center, but form structures different from those seen with gold. The basis of the discrimination of the anion between main group and transition metal halides is explored computationally, and the ditopic, ambiphilic reactivity of the anions is discussed.